Bare wire bank assembly



y 1960 F. R. EDGARTON BARE WIRE BANK ASSEMBLY Filed May 7, 1957 INVENTOR.

FRANK R. EDGARTON BY% W AGENT United States Patent BARE WIRE BANK ASSEMBLY Frank R. Edgar-ton, Los Angeles, Calili, assignor, to General Dynamics Corporation, Rochester, N.Y., a corporation of Delaware Application May 7, 1957, Serial No. 657,526

2 Claims. (Cl. 317-112) My invention relates to wire bank assemblies and more particularly to wire bank assemblies suitable for use in conjunction with telephone switching systems.

It is the practice in certain types of telephone switching apparatus to provide a bare wire bank multiple accessible to the wiper sets of each of a group of switches, the switches being spaced apart from each other along the length of the multiple. Such an arrangement is shown and described in U.S. Patent 2,506,730 to F. A. Morris. Such wire banks have been made from a group of substantially identical assemblies where each assembly includes two closely spaced, parallel rows of wires, the wires in each row being maintained evenly spaced apart from each other along their lengths. In order to hold the wires in their positions relative to each other, the wires are passed through suitably spaced openings or bores in a plurality of insulator blocks where the insulator blocks may be located at even intervals along the length of the assembly. In the past such assemblies have been manufactured by either: (1) aligning the blocks in the space relationship which they bear in the final assembly, shooting each of the wires through its corresponding opening in each block, and thereafter securing the insulator blocks to the wires by use of cement or other suitable methods; or, (2) aligning the rows of wires relative to each other in the space relationship which they occupy in the final assembly, advancing the positioned wires into a suitably shaped cavity of a mold, and thereafter inserting material into the cavity to form an insulator block around the wires, opening the mold and thereafter advancing the wires so that another section of the wires lie within the cavity of the mold and so that the process of forming an insulator block may be repeated. The first outlined method has the disadvantage that it is not a continuous process and requires separate cementing operations to be performed at each insulator block after the assembly has been removed fom the jig in which it is formed. The second outlined method has the disadvantage that the required close spacing between the rows of wires prevents, as a practical matter, the use of a mold capable of totally surrounding each wire, so that debris from the molding process is deposited on the wires adjacent to the insulator blocks.

Accordingly, it is an object of my invention to provide a new and improved assembly for use in making bare wire bank multiple.

Another object of my invention is to provide a new and improved assembly comprising substantially identical first and second subassemblies for use in making bare wire bank multiple.

Another object of my invention is to provide a new and improved wire bank subassembly which can be formed by molding in place insulating blocks which are used for positioning the wires.

Another object of my invention is to provide a new and improved wire bank subassembly which can be formed by molding in place the insulator blocks used for 2 positioning the wires without depositing substantial quantities of molding debris on the wires adjacent to the blocks.

Another object of my invention is to provide a new improved wire bank subassembly which can be formed by a continuous process.

Fora better understanding of my invention, reference is made in the following description to the drawing attached to and forming a part of the present specification, and in which:

Fig. 1 shows a side view of a wire bank assembly;

Fig. 2 shows a plan view of the assembly taken through section 2--2 of Fig. 1; and,

Fig. 3 shows an exploded view of a wire bank assembly showing how the subassemblies are joined together.

The wire bank assembly forming the preferred embodi ment of my invention includes first and second pluralities of round, substantially straight conductors 2, arranged in first and second parallel rows, the wires in each row being equally spaced apart from each other. Referring to Fig. 3, because the assembly consists of substantially identical leftand right-hand subassemblies, the same numbers are used to refer to corresponding elements in each subassembly. In the following description, in order to indicate which of the subassemblies is being considered, the first or left-hand subassembly elements are followed with the identifying letter a, while the second or right-hand subassembly elements are followed with the identifying let-' ter 1).

The first subassembly includes a first plurality of wires 2a which are carried and fixed relative to each other by a plurality of identical, substantially rectangular insulator blocks 1a, the blocks being distributed along the lengths of wires 2a at a distance 0 between centers (as indicated in Fig. 1). Each of wires 2a is received within one of a row of bores which pass through blocks 1a from top to bottom. The bores are equally spaced apart from and are parallel to each other. The diameter of each bore is substantially the same as the diameter of the one of wires 2a received therein, so that the surface of that portion of wire 2a lying within each of blocks 1a is substantially in engagement with the surface formed in the block 1a at the bore, whereby the blocks are fixed relative to wires 2a.

At the points in the top and bottom surfaces of blocks 1a at which conductors 2a emerge; a series of conical projections 3a is formed. Each section is integral with each of the blocks. Each of projections 3a is substantially coaxial with the corresponding one of wires 2a and surrounds that wire for a predetermined distance from the adjacent block surface. The function of conical sections 3a is to increase the leakage resistance of the subassembly (caused by surface conduction) between adjacent ones of conductors 2a by increasing the length of the physical path between adjacent conductors.

Each of insulator blocks 1a has a series of slots in one of its sides. The slots are of uniform width (substantially equal to the diameter of wires 2a) and are parallel to each other and to the axes of the previously referred to bores. The number of slots is equal to the number of wires in the above referred to second plurality of wires. Adjacent ones of the slots are separated from each other by a distance equal to the distance separating adjacent ones of the above referred to bores. Each slot terminates at its inner end in a cylindrical surface having a semicircular cross section and a diameter substantially the same as the diameter of wires 2a. The axes of the semicircular surfaces are oriented so that they lie in a single plane, the plane being parallel to another plane defined by the axes of the wire receiving bores. The axes of the semicircular surfaces are individually parallel to the wire receiving bore axes.

The. second, right-hand subassembly is substantially identical with the above described left-hand subassembly.

For this reason, a detailed description of the right-hand subassembly is not necessary for an understanding of my invention. 4

The assembly is formed as indicated in Fig. 3 by bringing together the above mentioned leftand right-hand subassemblies (cut to any convenient length) in a conjugate relationship; i.e., starting with the identical leftand right-hand subassemblies in the same space orientation, the right-hand section is rotated through 180 about an axis taken through its length and placed so that the slotted sides of the leftand right-hand subassembly insulator blocks face each other. The right-hand subassembly is then displaced by a distance c /2 along its length with respect to the left-hand subassembly as indicated in Fig. 1, so that insulator blocks 1 in the assembly are alternately borne by the leftand right-hand subassemblies and are equally spaced apart from each other along the length of the assembly. The subassemblies are brought together so that the wires 2a of the left-hand subassembly are received within the slots of blocks 1b carried by the righthand subassembly and thereby positioned with respect to the right-hand subassembly. Similarly, the second plurality of evenly spaced apart conductors 2b in the second subassembly are received within the slots of insulator blocks 1a, whereby conductors 2b are maintained positioned with respect to the left-hand subassembly.

In the foregoing description, I have set forth a Wire bank assembly including a subassembly of parallel wires which is adapted to be formed by the cycle of operations including the following steps: starting with a row of conductors positioned parallel to and equally spaced apart from each other, (1) introducing a section of the positioned wires within the cavity of an injection mold where a slotted block of insulating material is formed around the wires, (2) opening the mold (which is broken through a section including the axes of the wires), (3) advancing the block bearing portion of the subassembly in a direction along the length of the wires for a prescribed distance so that a different section of wires then lies within the cavity of the mold, and (4) repeating the steps outlined in (l), (2) and (3) above. Wire bank multiple formed from subassemblies made in the above outlined manner have the advantage that the operation can be made continuous, the number of operations is reduced to a minimum, and the mold used for forming the insulator blocks may be broken along a line passing through the axes of the wires, whereby the wire receiving orifices of the mold are formed to tightly enclose each wire and v a 4 thereby prevent the deposit of debris or flash on the wires surface external to the mold.

While I have shown and described a specific embodiment of my invention, other modifications of my invention will readily occur to those skilled in the art. I, therefore, do not desire my invention to be limited to the specific arrangement shown and described, and I intend to cover in the appended claims all modifications lying within the spirit and scope of my invention.

What I claim is:

i. In a wire bank assembly including first and second substantially identical subassemblies, each of said subassemblies comprising a plurality of wires and a plurality of identical subsantially rectangular insulator blocks, each of said blocks having a row of parallel evenly spaced apart bores passing therethrough from top to bottom and a plurality of evenly spaced slots in a side thereof, the number of said bores and said slots being equal to the number of Wires, the distance between adjacent ones of said slots being equal to the distance between adjacent ones of said bores, said slots being parallel to the axes of said bores,

each of said wires being received within a corresponding one of said bores in each of said blocks, said blocks being equally spaced apart from each other along the length of said wires, said subassemblies being positioned in conjugate relationship to each other, said second subassembly being displaced from said first subassembly along its own length, each of said subassembly wires being received Within a corresponding one of said slots in each of said insulator blocks incorporated in the other of said subassemblies, whereby said wires of said wire bank assembly are positioned relative to each other by said insulator blocks and said insulator blocks are alternately borne by said first and said second subassemblies along the length of said wire bank assembly.

2. The assembly set forth in claim 1 wherein said second subassembly is displaced along its own length from said first subassembly by a distance equal to half the distance separating adjacent ones of said insulator blocks borne by said second subassembly.

References Cited in the file of this patent UNITED STATES PATENTS 2,226,666 Lienzen Dec. 31, 1940 FOREIGN PATENTS 57,819 Sweden Jan. 11, 1923 585,137 Great Britain Jan. 30, 1947 

